JP5000633B2 - Start-up method for direct heating system for flameless combustion of fuel and direct heating of process fluid - Google Patents

Description

The present invention claims the benefit of US Provisional Application No. 60 / 660,448, incorporated herein by reference.
The present invention relates to a method for starting a direct heating device or system.

  A number of different types and designs of flameless combustion heating devices are disclosed in the known literature. For example, US Pat. No. 5,255,742 discloses a method of heating a subterranean formation using a flameless combustion device. The apparatus includes a fuel gas conduit having a plurality of orifices. The fuel gas conduit is centered in the combustion air conduit and forms a first portion between the fuel gas conduit and the combustion air conduit. The orifice allows communication between the fuel gas conduit and the first part. The combustion air conduit is concentrated in the center of the well casing, thereby forming a second annulus between the combustion air conduit and the well casing. The fuel gas is introduced into the first part via the orifice of the fuel gas conduit, mixes with air and burns in the first part. A first part formed by the combustion air conduit is capable of communicating with the second annulus between the combustion air conduit and the well casing. This circulation provides a flow path for the combustion gas that is introduced into the second ring portion and travels up to the surface, thereby supplying heat transferred to the underground.

US Patent Publication No. 2003/0182858 describes a method of applying controlled heat to a process fluid using a flameless distributed combustion device. The apparatus includes a fuel conduit that has a plurality of fuel nozzles and an ambient oxidation chamber distributed along the length of the nozzle. The conduit surrounding the fuel conduit forms an oxidation chamber. The apparatus further includes a process chamber that surrounds the oxidation chamber. The fuel nozzle communicates from within the fuel conduit to the oxidation chamber. In the oxidation chamber, the oxidant and the fuel are mixed and the fuel burns. The heat released by this combustion is transferred to the process chamber.
US Patent Publication No. 2004/0033455 describes an integrated combustion reactor in which the combustion chamber is in direct thermal contact with the reaction chamber for an endothermic reaction. It is further described to start the system with process reactants preheated to 260-290 ° C, combustion air preheated to 160-170 ° C, and a fuel stream of hydrogen that was not preheated outside the system.

Said document does not teach a four-tube flameless combustion heating device for heating process fluids, and in particular, the multiple tubes of the heating device are diversified together in the heat exchange system by the use of multi-tube plates. In this case, it does not recognize the difficulty that can occur with the start-up of a three-tube or four-tube flameless combustion device from the cold. When starting to use a flameless combustion apparatus from cold, one consideration is that when various input streams are introduced into the cooling apparatus, the introduced fuel may not be stably burned. Another consideration is that during cold start, it can occur in a flameless combustion device, but unsteady state operation is difficult. Also consider the effects of metal expansion in flameless combustion devices during cold start.
US Pat. No. 5,255,742 US Patent Publication No. 2003/0182858 US Patent Publication No. 2004/0033455

  Thus, it is an object of the present invention to provide a method for starting and using a heating device directly when not in use or cold.

  Accordingly, a method for starting a direct heating system is provided that includes a fuel introduction zone, a combustion zone, and a process zone in heat exchange relationship with the combustion zone. The method includes passing a thermal oxidant fluid through the combustion zone and a warm-up time sufficient to raise the temperature of the direct heating system to the desired temperature, and passing steam directly into the process zone and the temperature of the direct heating system. Passing for a second time sufficient to adjust to the desired temperature, and passing the fuel-containing fuel fluid through the fuel introduction zone after reaching the desired temperature and the second desired temperature.

  Another embodiment of the present invention is a method for starting a direct heating system comprising a fuel introduction zone, a combustion zone, and a process zone in heat exchange relationship with the combustion zone. The method includes passing a thermal oxidant fluid through the combustion zone and a warm-up time sufficient to raise the temperature of the direct heating system to the desired temperature, and after reaching the desired temperature, the process stream containing the process fluid is Passing through the process zone a second time sufficient to raise the temperature of the direct heating system to a second desired temperature, and after reaching the second desired temperature, a fuel-containing fuel fluid is passed through the fuel introduction zone. Process.

FIG. 1 is a simplified diagram showing a three-tube flameless combustion apparatus that is the subject of the starting method of the present invention.
FIG. 1B is a simplified diagram illustrating an embodiment of a three-tube flameless combustion apparatus that is the subject of the start-up method of the present invention.
FIG. 2 is a simplified diagram showing a four-tube flameless combustion apparatus that is the subject of the starting method of the present invention.
FIG. 2B is a simplified diagram illustrating an embodiment of a four-tube flameless combustion apparatus that is the subject of the start-up method of the present invention.

  The present invention provides a method of starting and using a flameless combustion device or direct heating system from cold. The direct heating system that is the subject of the start-up method described here is any type of heating system that combusts fuel and transfers this released thermal energy directly to the process fluid.

  The direct heating system of the present invention is often referred to as a flameless combustion device, a flameless combustion system, a flameless distributed combustion (PDC) device, etc., and the fuel increment is determined by the self-ignition temperature of the resulting mixture. These integrated heating systems are intended to burn the fuel under conditions that introduce it into a preheated oxidant stream at temperatures above. The fuel and oxidant streams should be mixed quickly and the oxidant stream speed should be such that it prevents flame formation so that the combustion reaction is not limited in any way by the low mixing speed. Should. The heat released by this so-called flameless combustion is configured to be in a heat exchange relationship with the combustion zone of the flameless combustion device, for example, by a process sleeve surrounding the combustion tube of the flameless combustion device, the oxidant introduction tube, or both. Should be transferred to the process fluid or process stream through the process zone.

  Some possible flameless combustion devices considered here are three-tube or four-tube flameless heating systems. The three-tube flameless heating system is a system including a fuel introduction zone, a combustion zone, and a process zone. The fuel introduction zone is defined by a fuel tube that introduces fuel into the combustion zone having a plurality of openings or orifices along the length of the tube. A combustion tube outside and surrounding the fuel tube defines a combustion zone through which the preheat oxidant fluid passes and mixes with the fuel. Fuel is introduced into the combustion zone via an opening in the fuel tube. The process tube outside and surrounding the combustion tube defines a process zone through which the process fluid passes. The process zone is further configured to be in a heat exchange relationship with the combustion zone.

  In some embodiments, the three-tube flameless heating system may include a fuel tube, an oxidant tube, and a process tube. The fuel tube has a length and a tube wall defining a fuel introduction zone and a combustion zone having a fuel pretropy in the length direction and within the fuel introduction zone. Here, the fuel pre-tropical zone includes a fuel inlet for introducing fuel into the fuel pre-tropical zone, and a fuel outlet for introducing preheated fuel from the fuel pre-tropical zone into the combustion zone, and is parallel to the combustion zone and is a pipe. There are multiple openings through the wall. The oxidizer tube is outside and surrounds the fuel tube, thereby defining an oxidant introduction zone along the length of the fuel tube. Here, the oxidizer introduction zone has an oxidizer pretropical zone and a fuel combustion zone. And a plurality of openings for allowing the combustion zone and the fuel combustion zone to flow. Outside the oxidizer tube and enclosing it, thereby defining a process fluid introduction zone in parallel with the oxidizer tube. Here, the process fluid introduction zone has a process fluid heating zone and an oxidant / fuel heating zone, and the process fluid heating zone is in a heat exchange relationship with the fuel combustion zone, so as to introduce the process fluid into the process fluid heating zone. A process fluid inlet and a process fluid outlet for introducing the heated process fluid from the process fluid heating zone into the oxidant / fuel heating zone. The oxidizer / fuel heating zone is also in heat exchange relationship with both the oxidizer pre-tropics and the fuel pre-tropics and includes a discharge outlet for discharging the heated process fluid from the oxidizer / fuel heating zones.

  The three-tube flameless heating system is disclosed in Process No. 1 of the co-pending patent application entitled “Heat transfer system for fuel combustion and process fluid heating, and method of using the system”. TH2699, the disclosure of which is incorporated herein by reference.

  The four-tube flameless heating system is a system including a fuel introduction zone, a combustion zone, an oxidant introduction zone, and a process zone. The fuel introduction zone is defined by a fuel tube that introduces fuel into the combustion zone having a plurality of openings or orifices along the length of the tube. The reaction tube or combustion tube outside and surrounding the fuel tube defines a combustion zone through which the preheat oxidant fluid passes and mixes with the fuel. Fuel is introduced into the combustion zone via an opening in the fuel tube. An oxidant introduction tube that is outside and surrounds the combustion tube and is preheated before the oxidant fluid passes through the oxidant introduction tube and into the combustion zone defines an oxidant introduction zone. The process tube outside and surrounding the combustion tube defines a process zone through which the process fluid passes. The process zone and the oxidant introduction zone are configured to have a heat exchange relationship directly or indirectly with the combustion zone.

  In some embodiments, a four-tube flameless heating system may include a fuel introduction zone, a combustion zone, an oxidant introduction zone, and a process zone in a concentric relationship. Here, the fuel introduction zone is defined by fuel introduction means for introducing fuel into the combustion zone, the combustion zone is defined by a reaction tube outside and surrounding the fuel introduction means, and the oxidant introduction zone is reacted. The process fluid zone is defined by the process tube outside and surrounding the oxidant tube, and is defined by the oxidant tube outside and surrounding the tube.

  In some embodiments, the four-tube flameless heating system may include a process system having a fuel tube having a fuel tube length and a fuel tube wall defining a fuel introduction zone. Here, the fuel pipe has a terminal portion and a fuel inlet end portion for introducing fuel into the fuel introduction zone, and has a plurality of openings in the length direction of the fuel pipe and through the pipe wall. is there. The process system also includes a reaction tube having a length of the reaction tube and disposed outside and surrounding the fuel tube, thereby defining a combustion zone along the length of the fuel tube. Here, the reaction tube includes a reaction tube inlet end for receiving the preheated oxidant into the combustion zone, and an exhaust end for discharging combustion exhaust from the combustion zone, and the plurality of spaced openings are provided. Makes it possible to circulate between the fuel introduction zone and the combustion zone. The process system further includes an oxidant introduction tube having a length of the oxidant introduction tube and disposed outside the reaction tube so as to surround and thereby define an oxidant introduction zone along the length of the reaction tube. Prepare. Here, the oxidant introduction pipe includes an oxidant introduction pipe inlet end for introducing the oxidant into the oxidant introduction zone, and an oxidant capable of circulating the preheating oxidant from the oxidant introduction zone and the reaction pipe inlet end. And an oxidant introduction pipe outlet end for discharging to the combustion zone via the introduction pipe outlet end, and the oxidant introduction zone is in a heat exchange relationship with the combustion zone. Furthermore, the process system comprises a process tube disposed outside and surrounding the oxidant introduction tube thereby defining a process fluid zone in parallel with the oxidant introduction tube. Here, the process tube comprises a process fluid inlet end for introducing process fluid into the process fluid zone, and a process fluid outlet end for discharging heated process fluid from the process fluid zone, the process fluid zone being It has a heat exchange relationship with the combustion zone.

  A four-tube flameless heating system is disclosed in Process No. 1 of the co-pending patent application entitled "Multi-tube heat transfer system for fuel combustion and process fluid heating and use of the system" TH2700, the disclosure of which is incorporated herein, is described in detail.

  The method of the present invention is a method of starting a flameless heating system such as the above-described three-tube type and four-tube type flameless heating system from cold. This starting method includes a series of steps that begin by introducing and passing a thermal oxidant fluid through the combustion zone of a flameless heating device. The thermal oxidant fluid is any suitable fluid that can be heated to a desired temperature prior to introduction into the combustion chamber. In some embodiments of the invention, the oxidant may be heated by external means. For example, the oxidant may be heated in the process itself.

  The thermal oxidant fluid is passed through the combustion zone for a warm-up time sufficient to raise the temperature of the flameless combustion device to the desired temperature. The time required to raise the temperature of the flameless combustion device to the desired temperature depends on the device mass, the device manufacturing material, the starting temperature of the device, and the desired temperature of the device.

  The desired temperature of the flameless combustion device can be determined or measured by any suitable means or method. The preferred method of measuring when the flameless combustion device reaches the desired temperature is to measure the inlet temperature of the thermal oxidant fluid introduced into the combustion zone of the flameless combustion device and after passing through the combustion zone, It is a method of measuring the exit temperature of the thermal oxidant fluid as it exits.

  Generally, when a thermal oxidant fluid is first introduced into the combustion zone, the exit temperature of the thermal oxidant fluid exiting the exhaust outlet of the flameless combustion device is the thermal oxidant fluid introduced via the combustion zone inlet of the flameless combustion device. Significantly lower than the inlet temperature. This large temperature difference between the inlet and outlet temperatures of the thermal oxidant fluid is due to heat transfer from the thermal oxidant fluid to the material and body of the flameless combustion device, but when the thermal oxidant fluid passes through the combustion zone. Since the flameless combustion apparatus is heated up and the outlet temperature of the thermal oxidant fluid is increased, the temperature difference between the inlet temperature and the outlet temperature of the thermal oxidant fluid is reduced.

  The temperature difference between the inlet temperature and the outlet temperature can be monitored during the measurement time when the temperature of the flameless combustion device reaches the desired temperature. The temperature difference or absolute temperature of the thermal oxidant fluid at the combustion zone exhaust outlet can be used as a temperature indicator for a flameless combustion device.

  The thermal oxidant fluid may be selected from any suitable fluid that can carry heat, ie, has a sufficient heat capacity. A preferred oxidant fluid used in the process of the present invention is an oxygen-containing fluid such as air, preferably air. The thermal oxidant fluid may contain water vapor as part of it. Thus, the thermal oxidant fluid preferably contains air and may further contain water vapor. At the beginning of a warm-up process using a thermal oxidant fluid, a predecessor such as passing steam through one or more zones of a flameless combustor for purposes such as purging the system or even warming up the system. It can be seen that the stage is not excluded. In some embodiments, the process step is performed prior to initiating the warm-up step with the thermal oxidant fluid. For example, water vapor may be passed through any one or more zones of the heat transfer system for purposes such as purging the system or even warming the system.

  The inlet temperature of the thermal oxidant fluid may be at least as high as necessary to heat the flameless combustion device as desired. In typical embodiments, the inlet temperature of the thermal oxidant fluid is about 200 ° C. (392 ° F.) to about 2000 ° C. (3632 ° F.) or about 260 ° C. (500 ° F.) to about 1000 ° C. (1832 ° F.). ), Preferably from about 360 ° C. (680 ° F.) to about 850 ° C. (1562 ° F.), most preferably from about 460 ° C. (860 ° F.) to about 725 ° C. (1337 ° F.).

  When the thermal oxidant fluid is first introduced into the combustion zone of the flameless combustion zone, the outlet temperature of the exhaust thermal oxidant fluid is significantly lower than the inlet temperature of the fluid as described above. However, this temperature difference decreases as the time for the thermal oxidant fluid to pass through the flameless combustion device increases. The desired temperature for the outlet temperature is greater than about 460 ° C. (860 ° F.), preferably greater than about 560 ° C. (1040 ° F.), and most preferably the desired temperature at the combustion zone outlet is about 620 ° C. (1148 ° F.). Should be exceeded.

  Once the desired temperature in the thermal oxidant fluid discharge is reached, in one embodiment of the start-up method, water vapor is introduced and passed through the process zone of the flameless combustion device as a process zone fluid. The temperature of the process zone fluid is measured and monitored in the same or similar manner as the combustion zone thermal oxidant fluid described above.

  The process zone inlet temperature of the steam process fluid may exceed the superheated steam temperature of about 425 ° C. (797 ° F.). The temperature of the water vapor introduced into the process zone is preferably greater than about 510 ° C. (950 ° F.), and most preferably greater than about 560 ° C. (1040 ° F.). It is particularly preferred that the temperature of the superheated water vapor exceeds about 620 ° C. (1148 ° F.).

  The steam is passed through the process zone for a second time sufficient to adjust the temperature of the flameless combustor to a second desired temperature. The second desired temperature can be measured by monitoring the temperature of the process zone fluid at the process zone outlet. The second desired temperature of the process zone outlet temperature is greater than about 460 ° C. (860 ° F.), preferably greater than about 560 ° C. (1040 ° F.), and most preferably the second desired temperature at the process zone outlet is about Should exceed 620 ° C (1148 ° F).

  Once either the desired temperature or the second desired temperature is reached, or both the desired temperature and the second desired temperature are reached, fuel fluid is introduced into the fuel introduction zone, enters the combustion zone through the fuel tube opening, It now mixes with the thermal oxidant fluid passing through the combustion zone and combustion begins. The combustion mixture comprising the fuel fluid and the thermal oxidant fluid is at a temperature above the autoignition temperature of the mixture. There is no need to add hardware or electronics to initiate or assist combustion. Sparks, igniters, glow plugs and other similar items are not required to initiate combustion.

  As the fuel fluid, any suitable fluid that can be combusted in the presence of an oxidant such as oxygen or air may be used. Examples of such fuels include hydrogen and hydrocarbons. Examples of hydrocarbons that can be used as fuel include hydrocarbons having 1 to 6 carbon atoms such as methane, ethane, ethylene, propane, propylene, propyne, butane, butylene, and butyne. Preferred fuels include those selected from hydrogen, methane, ethane and mixtures thereof.

  The fuel initially introduced into the fuel introduction zone during start-up of the flameless combustion apparatus may further contain water vapor in a part thereof. In this case, the mixture of fuel and water vapor passes through the fuel introduction zone and enters the combustion zone via the opening of the introduction zone, where fuel combustion occurs. After some time during combustion, the water vapor is removed from the fuel and the combustion of the fuel is continued in a flameless combustion device.

  In another embodiment, the water vapor is injected to purge the heating line. Fuel is introduced and the introduction of water vapor is stopped. Once the fuel ignites, a different fuel or fuel mixture can be introduced. Such fuel or fuel mixture may contain water vapor. Another embodiment includes starting without steam purge, injecting fuel without steam.

  Once both the desired temperature and the second desired temperature are reached, the process stream may be introduced and passed through the process zone of the flameless combustion device. The process stream is introduced into the process zone before the introduction of steam into the process zone, or after the introduction is stopped, or also at the same time as the introduction is stopped. Passed through. When the start of the flameless combustor is complete, fuel, oxidant fluid and process stream are being introduced into the respective zones. In some embodiments, the fuel may be a mixture of multiple fuels and / or contain water vapor.

  In another embodiment of the start-up method of the present invention, after reaching the desired temperature of the flameless combustion device, instead of passing steam through the process zone, a process stream is introduced and passed through the process zone of the flameless combustion device. The use of a process stream instead of water vapor is expected or will exist if the process stream is pre-heated under standard operation, at moderately high temperatures, or before the process stream is passed through the process zone. It may be particularly useful in situations where things are.

  An example of an embodiment where a process stream is expected to exist at moderately high temperatures is when a flameless combustor is used to introduce heat into a dehydrogenation process stream such as an ethylbenzene dehydrogenation stream in a styrene production process. is there. In this case, the temperature of the process stream at the process zone inlet is desirably greater than about 425 ° C. (797 ° F.). The temperature of the process stream introduced into the process zone is preferably greater than about 510 ° C. (950 ° F.), and most preferably the process inlet temperature is greater than about 560 ° C. (1040 ° F.). It is particularly preferred that the temperature of the process stream be greater than about 620 ° C (1148 ° F).

  Through the use of steam, the process stream is passed through the process zone for a second time sufficient to adjust the temperature of the flameless combustor to a second desired temperature. The second desired temperature may be measured by monitoring the temperature of the process zone fluid at the exit of the process zone. The second desired temperature of the process zone outlet temperature should be greater than about 460 ° C. (860 ° F.), preferably greater than about 560 ° C. (1040 ° F.), and most preferably the second desired temperature of the process zone outlet temperature is Should be above about 620 ° C. (1148 ° F.).

  Once either the desired temperature or the second desired temperature is reached, or both the desired temperature and the second desired temperature are reached, fuel is introduced into the fuel introduction zone and combustion begins within the combustion zone. The combustion mixture comprising the fuel fluid and the thermal oxidant fluid is at a temperature above the autoignition temperature of the mixture. There is no need to add hardware or electronics to initiate or assist combustion. Sparks, igniters, glow plugs and other similar items are not required to initiate combustion.

  In this embodiment of the start-up method of the present invention, the initially introduced fuel may further contain added steam. In this case, the mixture of fuel and added water vapor is passed through the fuel introduction zone and enters the combustion zone via the opening of the introduction zone, where fuel combustion occurs. After some time during combustion, the added water vapor is removed from the fuel and fuel combustion continues in the flameless combustion device. The process stream in this embodiment of the start-up method of the present invention may still further contain some amount of water vapor. Once the flameless combustion device is heated, the proportion of water vapor contained in the fuel fluid and the amount of water vapor contained in the process stream may be reduced.

Referring to FIG. 1, FIG. 1 is a simplified diagram showing a tube arrangement of a three-tube flameless combustion apparatus 100.
In one embodiment of the starting method of the present invention, a three-tube flameless combustion apparatus 100 comprising a fuel tube 102, a combustion tube 104, and a process tube 106 defining a fuel introduction zone 108, a combustion zone 110 and a process zone 112, respectively, is provided. Process is required.

  In most cases, the three-tube flameless combustion apparatus is started from the cold. A thermal oxidant fluid, such as air, is passed through the combustion zone inlet conduit 113 to the combustion zone 110 for a warm-up time sufficient to raise the temperature of the three-tube combustor 100 to the desired temperature.

  The desired temperature of the three-tube flameless combustion device 100 can be monitored and measured by measuring the outlet temperature of the thermal oxidant fluid as it exits the combustion zone 110 via the combustion zone outlet conduit 114. This combustion zone outlet temperature is related to the temperature indicator of the three-tube flameless combustion device 100 and is used as an indicator for the purpose of measuring when the temperature of the three-tube flameless combustion device 100 is the desired temperature. You can do it.

  Steam is introduced into the process zone 112 via the process zone inlet conduit 116 and passed through the process zone 112 for a second time sufficient to adjust the temperature of the three-tube flameless combustor 100 to a second desired temperature. . The second desired temperature of the three-tube flameless combustor can be monitored and measured by measuring the process side outlet temperature of the steam as it exits the process zone 112 via the process zone outlet conduit 118. The outlet temperature of water vapor from the process zone 112 is used as an indicator of the temperature of the three-tube flameless combustion device 100 for the purpose of measuring when the temperature of the three-tube flameless combustion device 100 is the second desired temperature. Related and may be used as an indicator.

  Once either the desired temperature or the second desired temperature is reached, or both the desired temperature and the second desired temperature are reached, fuel fluid is introduced into the fuel introduction zone 108 via the fuel introduction zone inlet conduit 120. The fuel fluid passes through the fuel introduction zone 108 and the opening 122 and is introduced into the combustion zone 110 where it is mixed with the thermal oxidant fluid and combustion occurs. Exhaust from the combustion zone 110 exits the combustion zone 110 via the combustion zone outlet conduit 114.

  Once fuel is introduced into the combustion zone 110 and combustion occurs, the water vapor passing through the process zone 112 may be replaced with a heated process fluid. Thus, a process fluid containing process stream is introduced and passed into the process zone 112. The process stream may be introduced into the process zone 112 at the same time as the introduction of water vapor into the process zone 112 is stopped, or before the introduction is stopped, or after the introduction is stopped. Thereafter, the start-up of the three-tube flameless combustion apparatus is almost completed.

Next, FIG. 2 will be described. FIG. 2 is a simplified diagram showing the arrangement of the tubes of the four-tube flameless combustion apparatus 200.
In another embodiment of the starting method of the present invention, a fuel tube 202, a combustion tube 204, an oxidant introduction tube 206 and a process tube defining a fuel introduction zone 210, a combustion zone 212, an oxidant introduction zone 214 and a process zone 216, respectively. A process of supplying a four-tube flameless combustion apparatus 200 with 208 is required.

  In a typical embodiment, the process zone is outside the oxidant introduction zone. Furthermore, in a typical embodiment, the oxidant introduction zone is outside the combustion zone. Furthermore, in a typical embodiment, the combustion zone is outside the fuel introduction zone.

  In most cases, the four-tube flameless combustion apparatus is started from the cold. Here, a thermal oxidant fluid such as air is introduced into the combustion zone 212 via the oxidant introduction zone inlet conduit 218 and the oxidant introduction zone 214, and then the thermal oxidant fluid enters the combustion zone 212 and the four-tube combustor 200. Is allowed to warm up for a sufficient time to raise the temperature to the desired temperature.

  The temperature of the four-tube flameless combustion apparatus 200 can be monitored and measured by measuring the outlet temperature of the thermal oxidant fluid as it exits the combustion zone 212 via the combustion zone outlet conduit 220. This outlet temperature is related to the indicator of the temperature of the four-tube flameless combustion apparatus 200 and is used as an indicator for the purpose of measuring when the temperature of the four-tube flameless combustion apparatus 200 is a desired temperature. Good.

  Steam is introduced into the process zone 216 via the process zone inlet conduit 222 and passed through the process zone 216 for a second time sufficient to adjust the temperature of the four-tube flameless combustor 200 to a second desired temperature. . The second desired temperature of the four-tube flameless combustor can be monitored and measured by measuring the process side outlet temperature of the steam as it exits the process zone 216 via the process zone outlet conduit 224. The outlet temperature of the steam from the process zone 216 is used as an indicator of the temperature of the four-tube flameless combustion apparatus 200 for the purpose of measuring when the temperature of the four-tube flameless combustion apparatus 200 is the second desired temperature. Related and may be used as an indicator.

  Once either the desired temperature or the second desired temperature is reached, or both the desired temperature and the second desired temperature are reached, fuel fluid is introduced into the fuel introduction zone 210 via the fuel introduction zone inlet conduit 226. The fuel fluid passes through the fuel introduction zone 210 and opening 228 and is introduced into the combustion zone 212 where it is mixed with the thermal oxidant fluid and combustion occurs. Exhaust from the combustion zone 212 exits the combustion zone 212 via the combustion zone outlet conduit 220.

  Once fuel is introduced into the combustion zone 212 and combustion occurs, the water vapor passing through the process zone 216 may be replaced with a heated process fluid. Thus, a process fluid containing process stream is introduced and passed into the process zone 212. The process stream may be introduced into the process zone 216 at the same time as the introduction of water vapor into the process zone 216 is stopped, or before the introduction is stopped, or after the introduction is stopped. Thereafter, the start of the four-tube flameless combustion apparatus is almost completed.

  While specific embodiments of the invention have been described herein, reasonable changes, modifications and adaptations of these embodiments may be made without departing from the scope of the invention as defined in the appended claims.

1 is a simplified diagram showing a three-tube flameless combustion apparatus that is the subject of the starting method of the present invention. It is a simplified diagram showing the embodiment of the three-tube type flameless combustion apparatus which is the subject of the starting method of the present invention. It is a simplified diagram showing the 4-tube type flameless combustion apparatus which is a subject of the starting method of the present invention. 1 is a simplified diagram showing an embodiment of a four-tube flameless combustion apparatus that is the subject of the start method of the present invention.

Explanation of symbols

100 Three-tube flameless combustion apparatus 102 Fuel tube 104 Combustion tube 106 Process tube 108 Fuel introduction zone 110 Combustion zone 112 Process zone 113 Combustion zone inlet conduit 114 Combustion zone outlet conduit 116 Process zone inlet conduit 118 Process zone outlet conduit 120 Fuel introduction Belt inlet conduit 122 Opening 200 Four-tube flameless combustion apparatus 202 Fuel tube 204 Combustion tube 206 Oxidant introduction tube 208 Process tube 210 Fuel introduction zone 212 Combustion zone 214 Oxidant introduction zone 216 Process zone 218 Oxidant introduction zone inlet conduit 220 Combustion zone outlet conduit 222 Process zone inlet conduit 224 Process zone outlet conduit 226 Fuel introduction zone inlet conduit 228 Opening

Claims (18)

  To raise the temperature of the direct heating system to a desired temperature in the combustion zone of a direct heating system comprising a fuel introduction zone, a combustion zone, and a process zone in heat exchange relationship with the combustion zone. Sufficient warm-up time, passing, steam passing through the process zone, and passing for a second time sufficient to adjust the temperature of the direct heating system to the second desired temperature, and to the desired and second desired temperatures. A method for starting a direct heating system comprising the step of passing a fuel-containing fuel fluid through a fuel introduction zone after reaching.   The method of claim 1, further comprising: stopping the passage of water vapor to the process zone after reaching the desired temperature and the second desired temperature, and passing a process fluid containing process stream through the process zone.   The method of claim 1 or 2, wherein the fuel fluid further comprises a proportion of water vapor. Further, the method of the placing serial to claim 3 including the step of reducing the proportion of water vapor in the fuel fluid. The method of claim 2, wherein the process stream further comprises an amount of water vapor. 6. The method of claim 5, further comprising the step of reducing the amount of water vapor in the process stream.   To raise the temperature of the direct heating system to a desired temperature in the combustion zone of a direct heating system comprising a fuel introduction zone, a combustion zone, and a process zone in heat exchange relationship with the combustion zone. Passing for a sufficient warm-up time, after passing the desired temperature, passing the process stream containing the process fluid through the process zone for a second time sufficient to raise the temperature of the direct heating system to the second desired temperature. And, after reaching the second desired temperature, a method for starting a direct heating system comprising passing a fuel-containing fuel fluid through a fuel introduction zone.   The method of claim 7, wherein the process stream further comprises an amount of water vapor.   9. A method according to claim 7 or 8, wherein the fuel fluid further comprises a proportion of water vapor. The method of claim 9, further comprising reducing the proportion of water vapor in the fuel fluid. 9. The method of claim 8, further comprising reducing the amount of water vapor in the process stream .   To raise the temperature of the direct heating system to a desired temperature in the combustion zone of a direct heating system comprising a fuel introduction zone, a combustion zone, and a process zone in heat exchange relationship with the combustion zone. Passing for a sufficient warm-up time, passing the steam through the process zone and, after reaching the desired temperature, a second time sufficient to raise the temperature of the direct heating system to the second desired temperature, and the desired A method for starting a direct heating system comprising the step of passing a fuel-containing fuel fluid through a fuel introduction zone after reaching a temperature and a second desired temperature.   13. The method of claim 12, further comprising introducing a process fluid containing process stream into the process zone. The method of claim 13, wherein the process stream further comprises an amount of water vapor.   15. A method according to any one of claims 12 to 14, wherein the fuel fluid further comprises a proportion of water vapor. The method of claim 14, further comprising reducing the amount of water vapor in the process stream . The method of claim 15, further comprising reducing the proportion of water vapor in the fuel fluid.   Supplying a direct heating device comprising a fuel introduction zone, a combustion zone, and a process zone in heat exchange relationship with the combustion zone, before introducing the fuel fluid into the combustion zone, Warm-up time sufficient to raise the temperature of the heating device directly to the desired temperature in the combustion zone, passing the superheated steam through the process zone, introducing steam into the fuel introduction zone before introducing the fuel fluid into the fuel introduction zone A step of passing through the belt, a step of introducing the fuel fluid into the fuel introduction zone in a gradually increasing amount to the fuel introduction zone, and then stopping the passage of the water vapor through the fuel introduction zone; A method for starting a direct heating device, the method including a step of stopping passage of the superheated steam after passing through the introduction zone.